Dr. Barbara Lane's expert presentation explaining fire testing standards, national classifications (BS 476), and their limitations for external wall fire scenarios.
00:00:13 good morning everyone welcome to today's hearing today we're going to hear a presentation by dr barbara lane on testing materials so
00:00:24 on testing materials so yes mr chairman before dr lane comes in i was just going to introduce what she was going to cover she's going to explain the national testing and classification regime including what is meant
00:00:35 including what is meant by class naught she's also going to explain the european testing and classification regime and also the large-scale testing which occurs under bs 8414 parts one and
00:00:46 which occurs under bs 8414 parts one and two
00:00:47 two and classification to br135 it will be an oral presentation only and not a question and answer session and before she starts i do need to give a trigger warning
00:00:59 a trigger warning about the presentation and some of its content
00:01:02 content there are included within the presentation some images and videos of fire scenarios and also included are some images of grenfell tower on the night and when on
00:01:13 grenfell tower on the night and when on fire
00:01:13 fire and some images of the damage to grenfell tower inside taken afterwards so it's important to give that
00:01:21 give that trigger warning for anybody who's watching and who would prefer not to see such material thank you very much so if i can now
00:01:28 i can now invite dr lane to come in to be sworn in and to give her presentation thank you
00:01:52 on your right hand
00:01:56 i swear by almighty god i swear by almighty god that the evidence i shall give
00:02:00 give that the evidence i shall give shall be the truth shall be the truth the whole truth the whole truth and nothing but the truth and nothing but the truth
00:02:08 the truth thank you very much dr layne good morning it's nice to see you again thank
00:02:20 you
00:02:34 so
00:02:42 yes dr lane if you'd like to go ahead and give your presentation thank you thank you very much
00:03:01 good morning throughout module two of this inquiry regular reference will be made to the products used to create the new external wall
00:03:09 wall during the grenfell tower refurbishment various fire performances will be referenced throughout the evidence various reaction to fire tests will also be referenced
00:03:21 to fire tests will also be referenced phrases such as national classes and national testing as well as european classes and european testing will become very familiar in the coming weeks in my presentation today i will explain
00:03:33 in my presentation today i will explain what those classes mean and how they were derived i will also explain
00:03:38 explain the reaction to fire tests upon which those classes rely reaction to fire tests are a particular form of fire test used to characterize the performance of
00:03:49 used to characterize the performance of construction products the approved document b refers to reaction to fire tests national classifications and european classifications
00:04:00 classifications when setting out the performance of products for use in external walls it is by means of national and european classes
00:04:08 classes the guidance document states that provisions are made to restrict the combustibility of external walls of high buildings also as stated at section 12.2 in the
00:04:20 also as stated at section 12.2 in the guidance documents these are the provisions to reduce the surfaces
00:04:25 surfaces susceptibility to ignition from an external source and to reduce the danger from fire spread up the external face of the building
00:04:35 building it is critical to understand the difference in definition for each class and the different reaction to fire tests associated with each class this complexity lies at the heart of
00:04:47 this complexity lies at the heart of accurately communicating external wall performance and fire as presented in section 12 of the approved document b this is a technically complex subject
00:04:59 this is a technically complex subject with many different fire tests classes and definitions it means there is a precision needed when communicating the provisions made
00:05:08 made in the statutory guidance documents and so when considering the external war products used at grenfell tower in general my presentation relies exactly on the text provided
00:05:20 exactly on the text provided in the relevant british and european standard
00:05:24 standard details most useful to wider activities within the test lab i have omitted as i do not consider them relevant to the explanations i'm giving here today but they can be found in the reference
00:05:36 but they can be found in the reference documents
00:05:37 documents and i have provided those references on the slides as i progress as part of my work for this inquiry with technical assistance from tom parker who is here with me today i've carried
00:05:49 who is here with me today i've carried out research into the history of these tests
00:05:52 tests classes and their definitions i have also analyzed how they have been presented over the years in the building regulations and the approved documents
00:06:03 approved documents the statutory guidance document approved document b 2013 was approved and issued by the secretary of state
00:06:11 of state for the purpose of providing practical guidance
00:06:14 guidance with respect to the requirements of the building regulations 2010 for england and wales my presentation focuses on this version and earlier versions it does not deal at
00:06:25 and earlier versions it does not deal at all with any changes that have occurred since the night of the grenfell fire
00:06:32 i have structured the presentation today into four main sections in doing this i will therefore explain in detail
00:06:39 in detail the eight reaction to fire tests referred to from within adb as well as the two larger scale cladding tests referenced there also in each section i will show
00:06:50 there also in each section i will show various
00:06:51 various images and movies and tom parker will also present the two scale models we built at arab of the specimens used in the eight reaction to fire tests
00:07:02 to fire tests we do not have the large cladding test samples due to their scale and so i will show images and movies of those clouding tests only after i explain some classic fire
00:07:13 after i explain some classic fire behaviors and how those behaviors were observed at grenfell i will then explain the four national reaction to fire tests and the definitions then used when setting out the national classes
00:07:25 setting out the national classes relied upon within approved document b i will show how these definitions have been relied on since 1965 and significant changes made to those definitions in that time
00:07:40 in section two i will explain the four european reaction to fire tests the european classification criteria and the resulting european classes relied upon
00:07:51 upon within approved document b i will explain the importance placed on the relevant field of application for products tested using european reaction to fire tests
00:08:02 reaction to fire tests i will set out how european classes are referred to from approved document b and then address some issues regarding equivalency when comparing the european classes with the national classes
00:08:14 the national classes finally in section 3 i will provide a summary description of both the performance criteria given in the bre report 135 which considers cladding
00:08:25 report 135 which considers cladding systems
00:08:26 systems not in individual products i will also explain the full-scale tests and data produced from the fire tests called british standard 8414 parts one and two
00:08:39 8414 parts one and two the data obtained from these tests is assessed
00:08:42 assessed using br 135 then a classification report can be produced for the clouding system tested i will explain earlier versions of these publications also
00:08:53 publications also and how they have been referenced from the statutory guidance documents over
00:09:07 the time thing i will present to you today relates to the basic signs of fire in a compartment or room a fire is characterized in a series of discrete stages for the purposes of scientific
00:09:19 for the purposes of scientific calculations and understanding and it is very useful to understand those stages and how they relate to the reaction to fire tests i'm setting out for you today
00:09:31 i thought it was useful to explain in brief how fires behave in compartments or rooms
00:09:37 or rooms because of what is stated in british standard 476 part 10. british standard 476 contains a series of fire tests four of which i'll be explaining in
00:09:48 four of which i'll be explaining in detail today they are the four national reaction to fire tests part 10 of this standard examines the principles objectives and outputs
00:09:58 outputs of fire testing in the bs 476 series offering guidance on selecting appropriate test methods it states reaction to fire tests are
00:10:10 it states reaction to fire tests are used to characterize the performance of construction products or materials in terms of their contribution to the initiation and growth stages of a fire leading up to flashover the underlying
00:10:23 leading up to flashover the underlying philosophy is that if a fire starts its rate of growth should be such that there is adequate time for the building occupants to escape to a place of safety without being
00:10:34 to a place of safety without being injured
00:10:38 i will summarize the discrete stages of a fully developed fire in a room or compartment in the next few slides this is a highly complex area of fire science and i make no attempt to cover
00:10:49 science and i make no attempt to cover the subject in depth my intention is to provide an overview of the classic behaviors upon which fire science relies after
00:11:00 upon which fire science relies after ignition the fire is typically initially small here at the three second photo
00:11:06 photo from an experiment carried out in the usa by nist it was burning with visible flame it then grows in size as shown at the 18 second
00:11:17 second image and the 32 second image this is the result of flame spread over the item first ignited and spreading to nearby objects if sufficient oxygen
00:11:28 sufficient oxygen is available at some point due to the enclosure surrounding this localized fire
00:11:35 fire and the available ventilation to that fire within the enclosure those parameters influence further fire development and so the power of the fire increases
00:11:46 and so the power of the fire increases with time
00:11:49 this graph represents the course of a well ventilated compartment fire expressed as the rate of heat release as a function of time within that compartment
00:12:00 compartment the internal compartment fire shown here is mostly divided into three substantial phases after ignition but also incorporating a short transition phase called flashover
00:12:12 transition phase called flashover so looking at the graph from left to right after ignition which occurs when fuel
00:12:17 fuel energy and oxygen are available in sufficient quantities to initiate combustion then we see the growth period on the graph this is flame and combustion leading to
00:12:29 this is flame and combustion leading to the ignition of additional fuel if sufficient oxygen is available then flashover can occur during the growth phase of a fire the thermal energy within the room
00:12:40 the thermal energy within the room increases to a point at which there is rapid ignition of the remaining unburned fuels provided there is sufficient oxygen afterwards is the fully developed fire
00:12:51 afterwards is the fully developed fire phase now the energy release is at its greatest
00:12:55 greatest in the room or compartment then decay as the fully developed flame starts to run out of fuel or oxygen flashover is therefore an important
00:13:06 flashover is therefore an important indicator
00:13:07 indicator of the onset of a fully developed fire and only occurs if there's sufficient air
00:13:12 air i recommend the drysdale reference for a more detailed
00:13:18 understanding
00:13:22 please watch this short video of an internal compartment fire growing
00:13:34 internal compartment fire growing yeah it doesn't seem to take just one second i don't think still i think i'll have to move on it was connected was meant to be connected to
00:13:42 to the internet
00:13:46 it's from the helmet cam of a firefighter in a room as a fire grows rapidly
00:13:50 rapidly i wonder is there a way of getting the movie to work
00:13:56 be very helpful yeah
00:14:00 yeah here we go thank you
00:14:04 watch how quickly the fire takes hold of the stacked timber in the corner and forms a smoke and flame layer at the ceiling within the room the flame spreads across the ceiling
00:14:15 the flame spreads across the ceiling seeking out ventilation along the corridor
00:14:21 the smoke and flame layer build down to floor level this room contains very little combustible material and so a prolonged fully developed fire cannot occur
00:14:33 so back to bs 476 part 10. it helpfully sets out what tests in the 476 series are relevant in the context of the classic room fire stages i have just summarized for you
00:14:46 stages i have just summarized for you it places the reaction to fire tests as relevant to the period of time before flashover flashover is marked with an x on this graph and the reaction to fire test references
00:14:58 and the reaction to fire test references can be observed in the red marked area underneath flashover the reaction to fire tests referred to for the external wall in the statutory guidance document are
00:15:09 in the statutory guidance document are therefore
00:15:10 therefore associated with pre-flash over our early-stage internal room fire growth there are other tests referenced by referenced by the british standard for
00:15:22 referenced by the british standard for the post flat over condition after the x marked on the graph here but what of reality as we saw at grenfell and have seen elsewhere
00:15:33 grenfell and have seen elsewhere i will now use some photos from the grenfell fire for the next five slides know that the fire spread from the external wall back into many flats that night then
00:15:46 back into many flats that night then caused a fully developed fire consuming everything in the room the result of which i have shown in the photo here and the fire curve representation of this fully developed fire is martin red
00:15:59 we know there was a prolonged decay phase in that it occurred at different times in all different parts of the tower
00:16:07 tower in this phase the rate of burning is diminishing the fuel is depleted of volatiles
00:16:12 volatiles the gas is formed when something is heated in a fire flaming eventually ceases and this stage leaves a mass of glowing embers this state may remain for long periods
00:16:23 this state may remain for long periods and there can even remain high localized temperatures again this behavior is concerned with the performance inside the building but we know too that there were
00:16:34 but we know too that there were different types of internal fire there were localized fires that night of a scale as i presented in the earlier nist experiment and shown on the left here
00:16:45 on the left here and i've seen for example at flat 16 the image here showing the internal localized fire but in this photo one can also see some external flaming
00:16:57 external flaming despite this room fire still being in its early growth phase only represented by the red area on the graph
00:17:08 and we know too that flat over did occur in many compartments and so fully developed fires were observed throughout the night the scale of these post flash over fires
00:17:19 the scale of these post flash over fires or fully developed fires are much larger and their consequences more severe than the pre-flat over conditions flames may emerge from ventilation openings such as windows
00:17:31 openings such as windows the threat to neighbouring compartments or adjacent buildings is then at its highest
00:17:36 highest the fire can spread through any internal openings such as doors or unsealed openings in the compartment so this is the stage of the fire when damage to structure becomes a concern
00:17:47 damage to structure becomes a concern it is the time of highest life safety risk to firefighters and it is too late for anyone who has not already left the compartment
00:17:58 but what about the external wall fire scenarios
00:18:02 scenarios we know that early in the night of grenfell and shown here at 126 an external fire event in the external wall had occurred in the beginning it was localized and external to one compartment
00:18:14 external to one compartment and then rapidly spread externally up the tower
00:18:18 the tower i hope mr chairman the panel can consider the following point this external scenario either when small or large
00:18:26 or large was separate to the internal room fire this internal fire behavior characterized by the temperature time graphs i've shown you today the external fire scenario is not the
00:18:38 the external fire scenario is not the same
00:18:38 same as the early stage fire behavior in a room
00:18:41 room the external fire is not controlled by the room enclosure or room ventilation phenomena
00:18:48 phenomena that cause classic room fire behaviors yet the statutory guidance document relies on reaction to fire tests for internal rooms bs 476
00:19:00 for internal rooms bs 476 part 10 states they are used to characterize the performance of construction products in terms of their contribution to the growth stages of a fire inside a room leading up to flashover only but pre
00:19:13 leading up to flashover only but pre and post flashover are not external fire phenomena
00:19:17 phenomena they are internal compartment phenomena but every reaction to fire test i explained today was apparently created to characterize performance in an internal room fire the tests are
00:19:30 in an internal room fire the tests are not deemed to be representative of external fire behavior if one relies on the british standard explanation in itself it would be useful to understand
00:19:41 understand why therefore they form such a fundamental part of the external wall of fire performance set out
00:19:48 set out in approved document b throughout today you will
00:19:52 you will also hear what those tests do demonstrate regarding the fire performance of materials and products and this is to assist you in your
00:20:04 deliberations
00:20:12 there are eight reaction to fire tests referenced within approved document b there are four national test standards and four european test standards the national tests from the british
00:20:23 the national tests from the british standard 476 series are parts 4 6 7 and 11. the european tests are not in a series and our four distinct
00:20:34 and our four distinct tests bsen 13823 bsen iso 1716 and 11925 part 2 and bsen
00:20:47 and 11925 part 2 and bsen 1182 where en means european norms and iso means international standards organization i will now explain the setup for each one of these tests
00:20:59 one of these tests how the test is then done and how the results from each test is then used and relied upon to classify the performance of construction products and materials
00:21:21 the foreign national reaction to fire tests are part of bs-476 series as i said
00:21:26 said each part addresses a different element of contribution in a fire part 4 is a test of non-combustibility for materials part 6 is a test of fire propagation for
00:21:40 part 6 is a test of fire propagation for products
00:21:41 products this means a comparative measure of the contribution to the growth of fire of a combustible material part seven is a test to classify the surface spread of flame of a product
00:21:54 the surface spread of flame of a product and part 11 is a test to assess the heat emission from materials
00:22:01 british standards are issued by the british standards institute there are specific subcommittees made up of industry and governmental bodies that draft
00:22:12 bodies that draft the standards the second page of the standards typically lists the parties involved in drafting the standard on screen now are examples taken from part 4
00:22:23 part 4 and part 6.
00:22:33 first i will explain part four the non-combustibility test for materials there has been one version of part four published and this was in 1970 with two further amendments made in 1978
00:22:47 with two further amendments made in 1978 and 1983 information was added to the forward
00:22:51 forward in 2014.
00:22:55 in 2014. the test apparatus for the part 4 test consists of an electric furnace which is switched on until the furnace temperature reaches a constant 750 degrees celsius
00:23:07 constant 750 degrees celsius for 10 minutes prior to the test the cuboid sample is placed in this furnace
00:23:14 furnace the furnace temperature is measured by a thermocouple positioned so that its hot junction is 10 millimeters from the wall of the furnace
00:23:22 furnace and at mid height of the specimen a thermocouple is a device for measuring temperature a second thermocouple is placed in the center of the specimen inserted from the top this shielded
00:23:35 inserted from the top this shielded thermocouple shall maintain contact with the material at the bottom of the hole drilled down halfway into the specimen
00:23:45 the image on screen shows a cross section through the furnace the key thing to observe here is that the heat is provided by running electricity through wire coils wrapped around a
00:23:57 through wire coils wrapped around a central tube made of alumina refractory material no direct flame impingement occurs in this test
00:24:08 three specimens are prepared each side a length of 40 millimeters with a height of 50 millimeters my colleague tom is now holding up an exact replica
00:24:20 exact replica of the size of the part 4 specimen
00:24:34 one complete test consists of testing three specimens each specimen tested separately in the furnace
00:24:41 furnace the specimen is placed in the specimen holder which is shown in the image on the left
00:24:46 the left this holder is a hundred millimeters high
00:24:51 high if the thickness of the material is less than the height required of 50 millimeters each specimen must then be made of a sufficient number of layers to achieve this thickness these layers should occupy a horizontal
00:25:03 these layers should occupy a horizontal position in the specimen holder and held together firmly without compression of the specimen by steel wires to prevent air gaps for composite materials of a thickness
00:25:15 for composite materials of a thickness such that an integral number of layers cannot be put together to give the specific size the thickness of the different components should be adjusted
00:25:24 adjusted so their proportions remain the same as the original specimen if either of these options cannot be followed the test must be performed on the
00:25:33 the individual component layers of the material and reported accordingly no part 4 test report has been submitted to the inquiry to date so i cannot confirm what option is
00:25:45 so i cannot confirm what option is typically used in practice for products associated with grenfell tower
00:25:53 i will now present a video of the test
00:26:08 procedure
00:26:36 um
00:26:56 [Music]
00:27:03 okay for a tested material to be considered non-combustible by means of this test
00:27:10 this test none of the three specimens during the test must either cause the temperature reading from either of the two thermocouples to rise by 50 degrees celsius or more above the initial furnace
00:27:22 or more above the initial furnace temperature or be observed to flame continuously for 10 seconds or more inside the furnace otherwise the material shall be deemed combustible
00:27:33 combustible the requirements of the test report are shown here with the single designation to be provided
00:27:40 provided that concludes my description of the part 4 noncombustibility test for materials
00:27:50 the second national reaction to fire test i will explain is part 11 which is the method for assessing the heat emission for building materials
00:27:59 materials this was current during the primary refurbishment and it is the national test for materials of limited combustibility the performance for insulation in external walls
00:28:11 external walls this standard has had no amendments and again information was added to the forward
00:28:16 forward in 2014 the fire vocabulary british standard
00:28:20 standard bs 4422 defines fire as the process of combustion characterized by the emission of heat and effluent accompanied by smoke flame
00:28:31 and effluent accompanied by smoke flame or glowing so the purpose of this test is to assess the heat emission it is done by measuring the temperature rise from the specimen as a result of being in a furnace as
00:28:42 as a result of being in a furnace as well as the specimen mass loss and any observed flaming during the test
00:28:50 the test apparatus in this heat emission test is similar to that used in the non-combustibility test but a notable exception being the design of the specimen holder
00:29:01 the specimen holder other amendments include a prescribed design for the electrical furnace windings
00:29:07 windings a mirror is proposed to allow the operator to observe flaming easier the apparatus also includes an additional support to the specimen insertion device
00:29:19 specimen insertion device part 11 also consists of an electric furnace with the power input to the furnace
00:29:25 furnace such that the temperature measured by the fermentedness thermocouple is stabilized at 750 degrees celsius this specimen holder has a circular base
00:29:36 this specimen holder has a circular base to accommodate cylindrical test specimens
00:29:40 specimens the furnace thermal thermocouple is to be located 10 millimeters from the furnace tube wall
00:29:47 wall and at a height corresponding to the midpoint of the furnace tube the specimen thermocouple is positioned at the geometric center of the specimen a third thermocouple is also added to
00:30:00 a third thermocouple is also added to allow a horizontal contact with the interior of the furnace wall the procedure for part 11 is similar to
00:30:11 the procedure for part 11 is similar to the non-combustibility test i've just explained
00:30:14 explained such that temperature measurements and flame observations are also taken however the duration of this test can be up to 120 minutes and the mass of the sample is obtained
00:30:26 and the mass of the sample is obtained before the tests this time five specimens must be prepared
00:30:33 prepared each one a cylinder 45 millimeters in diameter
00:30:36 diameter and 50 millimeters in height my colleague tom is now showing you an exact replica of a part 11 test
00:30:48 specimen
00:30:52 the specimen is then put into the holder as shown in the image on the left and again a thermocouple is inserted through a two millimeter drilled hole at the top of the specimen
00:31:04 at the top of the specimen again specimens must meet the minimum height required for the test specimen of 50 millimeters for a material with a normal thickness greater than 50 ml it should be reduced if the thickness of
00:31:16 it should be reduced if the thickness of the material is less than 50 mil the right height should be made using a sufficient number of layers of the material or adjusting the material thickness
00:31:31 the video on screen now shows this test
00:31:44 procedure
00:32:30 following the test two results are calculated first the furnace temperature rise is calculated as the maximum furnace temperature minus the final furnace temperature
00:32:41 the final furnace temperature secondly the specimen temperature rise is calculated by taking the maximum specimen temperature minus the final specimen temperature this is calculated for each of the five
00:32:53 this is calculated for each of the five specimens
00:32:54 specimens and an average value is obtained the average duration of total sustained flaming
00:33:01 flaming is also calculated for the five samples and recorded in the report the operator is also required
00:33:08 required to calculate and record the density calculate the rhythmic mean of the density
00:33:14 density calculate and record the mass loss of each individual specimen calculate the rhythmic mean of the mass loss of the pet specimens tested as a percentage these five measurements must be recorded
00:33:27 these five measurements must be recorded in the fire test report
00:33:32 it is a requirement of the test report that the following text is stated the results relate only to the behavior of the specimens of the material under the particular conditions of the
00:33:43 under the particular conditions of the test
00:33:44 test the results obtained on an individual material
00:33:47 material used in a combination should not be construed as reflecting the performance of the material combination as a whole which may be influenced by the mechanism of combining
00:33:59 influenced by the mechanism of combining the individual materials together such as with the diesels the results are not intended to be the sole criterion for assessing the potential fire hazard
00:34:10 for assessing the potential fire hazard of the material in use this is the important test for materials of limited combustibility noting no evidence of such a test has been submitted to the inquiry at this
00:34:21 been submitted to the inquiry at this time
00:34:30 the third national test i'll explain is 476 part 6. this is the method of test for fire propagation of products it is this test combined with the second
00:34:43 it is this test combined with the second test
00:34:43 test bs 476 part 7 which taken together form the basis of class naught about which you have heard and will continue to hear
00:34:53 to hear a lot about the fire propagation index is defined in the fire vocabulary british standard bs bs4422 as a comparative measure
00:35:05 bs bs4422 as a comparative measure of the contribution to the growth of fire of a combustible material this is a very different kind of reaction to fire test to those i've shown you so far today and part
00:35:15 part six relies on a different form of test apparatus
00:35:20 apparatus it was first published in 1968 since then three further versions were published with the most recent date of 2009 in 2014 this too
00:35:31 date of 2009 in 2014 this too had a change made to its forward the version relevant to the grenfell tower refurbishment was the 2009 version
00:35:42 the scope section of part six states this part of bs-476 specifies a method of test
00:35:51 of test the result being expressed as a fire propagation index that provides a comparative measure of the contribution to the growth of fire made by an essentially flat material
00:36:03 made by an essentially flat material composite or assembly it is primarily intended for the assessment of the performance of internal wall and ceiling linings
00:36:14 the test apparatus comprises a combustion chamber with the specimen holder that is fixed onto the front face the combustion chamber contains a horizontal gas burner tube
00:36:27 horizontal gas burner tube and two electrical heating elements and is surmounted by a removable steel chimney and cowl the specimen holder is made from calcium silicate board
00:36:39 silicate board having the same dry density and properties as that of the walls of the combustion chamber
00:36:46 chamber the holder is recessed to take a specimen of area two to five mil by two to five mil with a recessed depth of 12.5 25 or 50 millimeters depending on the
00:36:59 or 50 millimeters depending on the specimen to be tested a non-combustible compressible gasket one millimeters thick is provided for interposing between the specimen holder
00:37:11 specimen holder and the combustion chamber to assist in obtaining an adequate seal
00:37:19 on screen now is a close-up of the combustion chamber showing the three heat sources two electric heating elements and a gas burner as shown
00:37:30 and a gas burner as shown the internal dimensions of the combustion chamber are 190 millimeters by 190 millimeters and a depth of 90 millimeters i show a cross section on the next slide
00:37:44 i show a cross section on the next slide at the top of the combustion chamber is a chimney where hot gases can leave the chamber
00:37:52 as indicated by the dashed arrow the combustion chamber is 90 millimeters deep
00:37:57 deep it is useful to understand the depth of the specimen holder which is marked green
00:38:02 green and attached to the front face of the chamber
00:38:10 the image on screen shows the specimen being held up in front of the opening to the combustion chamber the opening to the combustion chamber recess is slightly smaller than the
00:38:21 recess is slightly smaller than the green specimen on the screen each specimen is square and measures 225 by 225 as i said my colleague tom is now holding up an
00:38:32 my colleague tom is now holding up an example of the part 6 specimen
00:38:48 whilst the sample is of dimension two to five millimeters the opening in the combustion chamber is 190 by 190 millimeters the result of this is that a boundary
00:39:01 the result of this is that a boundary around the edge of the sample is not directly exposed to the heat from the electric heaters and gas burner products with a normal thickness of 50 millimeters or less
00:39:12 millimeters or less are tested at full thickness for products of normal thickness greater than 50 ml the specimen is obtained by cutting away the unexposed face of the product
00:39:23 the unexposed face of the product to reduce the thickness to the required 50 ml
00:39:27 50 ml it is stated in the standard where the product is normally root used as a freestanding sheet then an airspace should be provided at the back of the product
00:39:38 the back of the product by testing over non-combustible perimeter battens where the specimen is backed by an air gap
00:39:47 gap ensure that the perimeter of the specimen will not permit flame to penetrate into the cavity similarly where a flame retardant coating is applied to a surface
00:39:58 coating is applied to a surface the edge detail shall be such as to prevent ignition of the underlying layers
00:40:05 layers this detailed information in this british standard emphasizes the importance of preventing heat transfer through the cut edges of the sample therefore
00:40:15 therefore this is to make sure the front face heating occurs only and that the fire propagation index calculated is as a result of this front face heating regime
00:40:26 heating regime only
00:40:31 part 6 also makes a clear statement on the influence of underlying layers on the performance of the assembly when being tested in this combustion chamber
00:40:42 combustion chamber it advises that increasing the thermal capacity
00:40:45 capacity of the underlying construction increases the heat sink effect and this may delay ignition of the exposed surface it states that care should be taken to
00:40:56 it states that care should be taken to ensure the result obtained on any assembly is relevant to its use and practice
00:41:07 its use and practice several options are then provided with regard to the preparation of the test specimen
00:41:12 specimen and if it can rest directly on the specimen holder or if it requires a substrate between it and the specimen holder and these are all shown
00:41:23 all shown on the screen here
00:41:35 on the screen here prior to the test the specimen holder is then firmly fixed in place as shown on screen
00:41:41 screen during the test both the gas burner and the two electric heating elements are used which i will explain later the temperature output from the thermocouples of the flue gases in the chimney
00:41:52 chimney is measured throughout the test with specific temperature measurements noted at set time intervals which i will also describe later
00:42:05 the image on screen now shows the rear of the apparatus this features an observation window and an air inlet below visual observations are made during the test through the window
00:42:17 test through the window these must include intumescence or deformation or spoiling of the specimen that tends to block the burner ports so the required gas input cannot be maintained or melting or
00:42:30 input cannot be maintained or melting or slumping of the specimen that results in material escaping from the air inlet or being confined to the recess of the specimen holder where it is not exposed to the heating
00:42:42 where it is not exposed to the heating conditions air flow through the apparatus being restricted owing to obstruction of the inlet port by fallen material or by soot accumulation in the chimney
00:42:55 or by soot accumulation in the chimney a current of any of the above phenomena shall deem the test on that specimen to be invalid [Applause] this test consists of data measured from
00:43:06 this test consists of data measured from two different materials as well as the specimen to be tested the test
00:43:12 test also requires a specimen of calcium silicate to be prepared calcium silicate is a non-combustible material
00:43:20 material and tom is now holding up a piece of that board for reference
00:43:37 in its board form it is used in the test combustion chamber as a benchmark and the data from the test specimen is then compared to the data obtained when the calcium silicate board is tested
00:43:49 the calcium silicate board is tested first
00:43:50 first only one calcium silicate specimen is required
00:43:53 required however at least three of the material specimens must be tested
00:43:59 i will now present a video of this test
00:44:06 procedure
00:45:10 [Music]
00:45:51 the output from the two thermocouples located in the chimney is recorded at some specific intervals we need to discuss at 0.5 minute intervals up to and
00:46:03 at 0.5 minute intervals up to and including three minutes from the time at which the gas was ignited and this is then converted to a parameter called s1 at one minute intervals up to and
00:46:14 at one minute intervals up to and including 10 minutes from the time at which the gas was ignited and this is then converted to a parameter called s2 two minute intervals
00:46:25 s2 two minute intervals up to and including 20 minutes from the time
00:46:28 time at which the gas was ignited which is then converted to a parameter called s3
00:46:36 all the visual observations should be recorded during the test as observed through the window as i have already explained
00:46:45 the ultimate output of this part six test is a parameter called the fire propagation index i and sub indices little i one little i2 and little i3
00:46:58 little i2 and little i3 these parameters are directly referenced by approved document b as shown on the screen as part of the fire definition of class naught it is critical people
00:47:09 of class naught it is critical people understand the fire propagation index and the sub indices only come from bs 476 part 6. i will now explain how the indices are
00:47:22 derived regarding the sub indices s1 s2 and s3 i've provided the formulae to calculate them circular circled in the green box which uses the
00:47:35 circled in the green box which uses the measured temperatures shown on the screen now these s values are then averaged and used to calculate little i 1 2 and 3 as shown in the orange box below
00:47:49 and 3 as shown in the orange box below sub index little i1 sub index little i2 and sub index little i3 are then summed to obtain the index of overall
00:48:00 summed to obtain the index of overall performance i of the product please just remember that the only measurement taken as part of this test methodology
00:48:11 methodology is the temperature from the thermocouples within the chimney at the top of the combustion chamber at set time periods which are then converted to temperatures
00:48:24 the standard specifies the required contents of the test report i particularly note the report must state
00:48:33 state details of the form in which the specimens were tested material composite or assembly together with specimen thickness and where appropriate orientation the backing material
00:48:45 backing material and the face or faces subjected to the test
00:48:48 test and whether the material was tested in a modified form the statement that the suffix are to the fire propagation index indicates that the results should
00:48:59 index indicates that the results should be treated with caution and the test report must contain the statement again the test results relate only to the behavior of the test specimens of the product
00:49:10 product under the particular conditions of test they are not intended to be the sole criterion
00:49:15 criterion for assessing the potential fire hazard of the product in use
00:49:21 the test setup is designed to prevent heating through the cut edges of the test specimen for a composite material therefore such as acm
00:49:31 as acm it would mean the outer aluminium surface is heated first and the products of combustion from any other material behind it should they receive sufficient heat
00:49:42 it should they receive sufficient heat together may cause a temperature rise in chimney
00:49:46 chimney this is why it is important to understand how much heat energy is applied to the sample in this standard test which has a duration of 20 minutes
00:50:04 i have found some historic work regarding this heating dose received on the surface of the specimen tested in part six in 1968 the bre issued fire note 710
00:50:17 in 1968 the bre issued fire note 710 titled the fire propagation test as a measure of the fire hazard of a ceiling lining as stated in the note
00:50:25 note part of the study involved measuring the rate of heat transfer to a specimen in the fire propagation test
00:50:36 on screen now i've shown some text explaining the heat exposure measurements produced in this paper this is for background information only because the key information i want to present
00:50:47 present is the graph referenced within this test sorry excuse me within this text this is figure one from fire note 710
00:50:58 this is figure one from fire note 710 and it shows the growth heat flow the heat flux received at and on the surface
00:51:05 surface of the asbestos wood sample used on the test
00:51:09 test the the paper for any fire scientists listening
00:51:13 listening defined the growth growth heat flow as the algebraic sum of the rates of heat transfer into the specimen pipe by conduction from the surface by radiation
00:51:24 radiation and from the surface by convection
00:51:31 so to understand if a similar heat received on a surface of a different type of specimen as a result of this scale of heating is then sufficient to ignite the specimen
00:51:42 then sufficient to ignite the specimen being tested i present the following i have compared the received heat measured in this paper on asbestos wood shown by the dark blue line on the
00:51:53 shown by the dark blue line on the screen
00:51:55 screen and i have compared it with critical heat flux values associated with the materials used in the
00:52:01 the external wall of grenfell tower i have done this purely to give a sense of scale
00:52:07 scale of the heating regime within the combustion chamber only fire note 710 states the growth heat transfer rates will be higher for good insulators
00:52:18 insulators although they will be of the same order and will vary with time in much the same way so it is reasonable in trying to understand the scale of heat applied
00:52:29 heat applied to the surface of materials in the part 6 test
00:52:33 6 test to rely on the dark blue line for comparison i have used dash lines to over mark the graph
00:52:40 graph with values of typical critical heat fluxes
00:52:44 fluxes needed for the piloted ignition of the materials
00:52:48 materials this is the ignition that occurs when a flame is impinged on the specimen i have provide i have provided those classic and typical values for pir foam and phenolic foam polyethylene
00:53:02 foam and phenolic foam polyethylene and wood therefore with the heating dose from the particles test the applied heat flux to the sample made of wood the wood would be expected to ignite
00:53:14 the wood would be expected to ignite between three and four minutes for polyethylene this would be after four minutes pir would ignite between four and five minutes
00:53:24 minutes and phenolic foam after eight minutes the part 6 test is a total duration of 20 minutes i note that the melting point of polyethylene is approximately 130
00:53:36 polyethylene is approximately 130 degrees celsius whereas the melting point of aluminium is over 660 degrees celsius based on the test report submitted to the inquiry
00:53:47 the inquiry when acm panels are tested in this apparatus
00:53:50 apparatus the aluminium can sometimes act as a protection to the polyethylene protecting it from direct flame exposure and therefore the polyethylene sometimes melts and flows away rather than ignites
00:54:03 melts and flows away rather than ignites within the panel during the test if it does not ignite the temperature is measured and the chimney are lower
00:54:14 i have now added to this comparison graph the time period when the temperatures forming the index s1 are actually calculated during this period please note the heat
00:54:26 during this period please note the heat exposure to the specimen is actually less than that required to ignite wood or polyethylene i have also marked the time periods when the temperature is forming the sub index
00:54:37 the temperature is forming the sub index s2 and s3 so excuse me forming little s2 and little s3 are also calculated
00:54:49 to sum up the part 6 test is the fire propagation index test and is based on the temperatures measured in the chimney the product tested is then assigned little s1 little s2 and a little s3 sub
00:55:03 little s1 little s2 and a little s3 sub index these are averaged across three tests
00:55:07 tests to obtain the sub-indices little i 1 2 and 3. the sub-index little i-1 is therefore an average of measurements taken
00:55:16 taken during the first few minutes of the test only when the heating dose is relatively low
00:55:23 low i have shown how little i1 is referred to
00:55:26 to in the adb on the screen marked on purple
00:55:30 purple there the adb also refers to a fire propagation index i this is the overall index and as and is based on the heating dose received over the 20 minute period
00:55:43 received over the 20 minute period composites can be tested however when they are tested the specimen is arranged to ensure
00:55:48 to ensure the front face heating of the specimen only
00:56:01 the fourth and final national reaction to fire test is bs 476 part 7 method of tests to determine the classification of the surface spreader flame of products
00:56:12 flame of products this must be combined with part 6 as i have just explained when understanding the derivation of class naught as set out in the adb i want to stress that class naught is
00:56:23 i want to stress that class naught is not simply a surface thread of flame test as so commonly stated only the part 7 test on its own is and there is no national class that
00:56:34 and there is no national class that relies solely on part 7. class naught is defined on the basis of the two tests and this is a critical distinction that must be incorporated in
00:56:45 must be incorporated in any evidence given to the inquiry regarding class naught there have been three versions of part seven published first in 1971 with two further revisions
00:56:57 first in 1971 with two further revisions in 1987 and 1997 and a change to the forward only in 2014
00:57:07 the forward section of part 7 states the test takes account of the combined effects of factors such as ignition characteristics and the extent to which the flame spreads
00:57:18 extent to which the flame spreads over the surface of the product under opposed flow conditions the influence of any underlying materials on these factors in relation to their ability to
00:57:29 in relation to their ability to influence the rate of fire growth is also taken into account the test result is a function of the distance and rate of the lateral spread of flame and this
00:57:40 of the lateral spread of flame and this is classified according to performance as classes 1 to 4. the scope section of part 7 states this this part provides data suitable
00:57:54 this this part provides data suitable for comparing the end-use performances of essentially flat materials composites or assemblies which are used primarily as the exposed surfaces of walls or ceilings
00:58:10 the scale of apparatus used in the part 7 test
00:58:13 7 test is very different to the other three national reaction to fire tests and relatively speaking is a much larger however it is still important to note how much smaller this sample size is
00:58:26 how much smaller this sample size is when considering the scale of a cladding panel used in construction i will show an image to help understand this later the part 7 apparatus consists consists
00:58:38 the part 7 apparatus consists consists of
00:58:38 of an 85 850 ml by 850 mil radiation panel mounted vertically in a surround
00:58:45 surround and supported on a framework the specimen holder protrudes perpendicular from the radiating surface a small pilot flame tube is also provided
00:58:56 flame tube is also provided as part of the apparatus
00:59:02 this is the largest specimen required for a national reaction to fire test and each specimen is a rectangle measuring 885 millimeters long
00:59:13 measuring 885 millimeters long and is 270 millimeters in height tom is now holding up an exact replica of the part 7 sample
00:59:35 when the product is of insufficient size to allow the specimen size to be achieved in width or length it is permissible for small pieces of the product to be placed adjacent to
00:59:46 the product to be placed adjacent to each other to obtain the required dimension providing that an essentially flat surface
00:59:52 surface can be achieved and it is considered in the test standard that such a procedure does not have any influence on the surface spread of flame but the use of such special specimens
01:00:04 but the use of such special specimens shall be reported the specimen holder comprises a water-cooled steel frame with water-cooled face plates the faceplates overlap the specimens by 20
01:00:17 faceplates overlap the specimens by 20 millimeters on their top and bottom edges
01:00:19 edges and over the vertical edge adjacent to the radiation panel a spring-loaded clamp is positioned to clamp the specimen against the water-cooled face plates
01:00:31 against the water-cooled face plates the water supply to the specimen holder is such that the maximum temperature does not exceed 35 degrees celsius at the outlet from the specimen holder
01:00:42 the specimen holder specimens are tested at full thickness so long as they fit into the test frame where a material is more than 50 millimeters it is cut down from the unexposed side
01:00:53 unexposed side to allow it to fit in the test position the specimen holder assembly is located at 90 degrees to the face of the radiation panel
01:01:04 radiation panel the height of the specimen holder assembly
01:01:07 assembly sorry excuse me the height of the specimen holder is such that the horizontal reference line marked on the specimen and shown on the screen here is brought to the mid height of the
01:01:18 is brought to the mid height of the radiation panel the specimen holder is hinged to allow it to be swung horizontally away from the face of the radiation panel between tests
01:01:29 panel between tests to assist with interpreting the results the specimen is marked with reference lines
01:01:34 lines before it is mounted into the test rig and these lines are at set distances as shown on the green face of the specimen on this slide
01:01:50 the part 7 standard sets out how the exposed face of each specimen shall be marked in detail on its surface the reference line with a reference
01:02:01 reference line along its length and 95 millimeters above its bottom edge to assist in the observation of flame travel the specimen shall be marked as intervals
01:02:11 intervals along its length with lines normal to the reference line and at intervals shown in figure 7 of the standard which is on screen now the four vertical
01:02:22 which is on screen now the four vertical lines that run full height are the classification limit distances along the sample for class 1 class 2 class 3 and class 4.
01:02:36 however there are another of other there are a number of other requirements for the specimen which i will briefly run through a minimum of six and a maximum of nine
01:02:47 a minimum of six and a maximum of nine test specimens shall be provided and they shall be representative of the exposed surface of the product the product shall be tested on that face which is normally exposed in practice
01:03:00 which is normally exposed in practice taking account of the of the following if it is possible for either are both of the faces to be exposed in use then if the faces are different or if
01:03:11 then if the faces are different or if the core of those faces is asymmetrical both faces shall be tested if the face of the product contains a surface irregularity that is specifically directional for
01:03:23 that is specifically directional for example corrugations the product shall be tested in both orientations if the exposed face contains distinct areas of different surface finish or
01:03:34 areas of different surface finish or texture
01:03:35 texture then the appropriate number of specimens shall be provided for each distinct area of such finish or texture
01:03:47 all specimens shall be tested out at full thickness or cut away as i explained earlier when the product is a thin film it should be applied to an appropriate substrate
01:03:58 appropriate substrate using a method and application rate recommended by the manufacturer the lab shall determine whether a product incorporates a thin film on its surface
01:04:08 surface and shall note if this is the case when the product is a material or composite which would normally be attached to a substrate it shall be tested in conjunction with
01:04:19 it shall be tested in conjunction with the appropriate substrate also using the fixing technique recommended by the manufacturer please note the significance that this standard makes to the effect of the underlying
01:04:31 to the effect of the underlying substrate and the reader is referred to part
01:04:35 part appendix b of part 7 for more information part 7 also provides a clear explanation regarding the impact of any underlying construction on the ignition
01:04:47 underlying construction on the ignition performance of the surface this test standard again provides rules on how the sample should be tested as a result
01:05:02 i will now explain the heating apparatus it essentially consists of a radiation panel mounted vertically in a surround and supported on a framework
01:05:13 and supported on a framework so that the center of the panel is 1.25 meters above floor level the radiation panel shall be supplied with a gas air mixture the radiation panel is 850 mil by 850
01:05:26 the radiation panel is 850 mil by 850 mil square designed to give efficient combustion of the air gas air mixture with no flaming occurring on the face of the panel under operational conditions
01:05:39 the radiation panel shall be fitted with a refractory concrete surround this around shall project from the face of the radiation panel on its four edges by 50 millimeters
01:05:51 by 50 millimeters any small gaps between the surround and the radiation panel shall be tightly packed with a flexible non-combustible insulating material a separate small
01:06:02 insulating material a separate small pilot flame is also provided in addition to the radiant heat panel and immediately adjacent to the test specimen
01:06:11 specimen this pilot burner shall consist of a steel tube with an internal diameter of nominal value three millimeters and an external diameter of nominal
01:06:22 and an external diameter of nominal value six point four millimeters the burner shall be designed in such a way that with the specimen in the test position
01:06:30 position the center of the burner is positioned exactly as set out in the standard which i have reproduced here [Applause]
01:06:42 [Applause] the video on screen now shows this test procedure
01:07:04 so do you mind if i just try and get the video to work yep oh yeah thank you apologies
01:08:34 throughout the test it is required to carefully observe the behavior of the product and make a note of the following phenomena
01:08:42 phenomena flashing transit transitory flaming observe and note other phenomena such as debris falling away from the specimen and whether it is flaming or not any
01:08:54 and whether it is flaming or not any intumescence or deformation of the specimen these additional observations do not influence the classification of surface spread of flame
01:09:05 part 7 sets out four classifications based on the spread of flame at 1.5 minutes
01:09:11 minutes and the final flame spread after 10 minutes
01:09:14 minutes these are class 1 class 2 class 3 and class 4
01:09:18 class 4 and the limits for each are on screen now
01:09:21 now [Music]
01:09:23 [Music] i also note that it is stated that this statement must be included in the test report
01:09:29 report again the test results relate only to the behavior of the test specimens of the product under the particular conditions of tests they are not intended to be the sole criterion
01:09:40 criterion for assessing the potential fire hazard of the product in use the inquiry panel should consider that only one of these four tests
01:09:52 only one of these four tests actually measures the rate of flame spread across a specimen and then the purpose of that test was to measure horizontal spread stated for a long walls and ceilings
01:10:07 i'm just going to do about two more slides
01:10:12 finally i want to explain what extending the fields of application means again a phrase that will be used over the coming months when referencing test reports and test standards
01:10:24 test reports and test standards as i've shown each test report for the national reaction to fire tests must contain specific information including the limits of what was physically tested
01:10:38 part 10 the guide to the principles of fire testing and their outputs states at paragraph 5.3 within the field of reaction to fire
01:10:49 within the field of reaction to fire direct field of application is the application of the test results for a material or product in accordance with the details of how they are tested specifically this means that the
01:11:01 specifically this means that the mounting and fixing arrangement used in the test method is applied directly to the use of material or product in real end-use conditions
01:11:12 in real end-use conditions any variation in the physical properties or thickness of material or product in the end use application or variations in the mounting and fixing arrangements should be either quantitatively
01:11:24 should be either quantitatively determined through a carefully designed test program or in some cases be the subject of an assessment or expert judgment by an expert
01:11:37 i am aware of one british standard that gives guidance on the application and extension of results but this focuses particularly on fire resistance tests
01:11:48 tests not reaction to fire tests there is also an
01:11:52 an industry document issued by the passive fire protection federation titled guide to undertaking assessments in lieu of fire tests this again sets out guidance on
01:12:03 this again sets out guidance on assessing the fire resistance performance of products and systems in lieu of undertaking further british british
01:12:11 british national fire tests both documents make passing references only to the reaction to fire tests within the industry document it states
01:12:22 within the industry document it states on page four examples of complex assessments are interpolation extrapolation of a range of test data to cover the reaction to fire
01:12:33 to cover the reaction to fire performance of a different thickness of a product i have not found any other publications for reaction to fire tests relevant at the time of works on grenfell tower
01:12:45 however one extended field of application report for a national reaction to fire test has been submitted to the inquiry this was done by xova warrington fire on
01:12:56 this was done by xova warrington fire on behalf of kingspan this was an assessment of the ability of a range of foil faced polyisocya insulation board materials
01:13:07 materials to comply with the requirements of class 1 when tested in accordance with part 7. no analysis is presented within this report
01:13:16 report just a statement no such field of application extensions have been submitted to the inquiry for cladding panels at this time i've provided my opinion on how the bba
01:13:29 i've provided my opinion on how the bba relied on a limited number of tests to issue a bba certificate for cladding panels
01:13:35 panels at length in my phase one report i wouldn't like now if possible to take a short break please yes well that's a very convenient moment thank you very much we'll break until
01:13:46 much we'll break until half-past eleven would that be suitable yes please yes thank you thank you
01:13:57 a fast eleven please
01:31:00 yes would you ask dr lane to come back in please thank you
01:31:18 yes dr lane well when you're ready to carry on with yeah thank you
01:31:45 i will now explain all the national classes
01:31:49 classes and their relationship with these four tests
01:31:54 so the first important point is there is no overarching british standard for the classification of products and materials to the national reaction to fire test regime
01:32:06 reaction to fire test regime there is in europe which we will discuss in the next section of this presentation instead the national classes rely on fire definitions by means of text in the statutory guidance document b
01:32:18 in the statutory guidance document b only
01:32:20 only the relevant definitions are non-combustible limited combustibility class 1 to 4 index i and sub index little i1 and class naught
01:32:39 these specific fire definitions were provided
01:32:42 provided within approved document b 2013 section 12 the external wall construction refers to these definitions both in the main text
01:32:53 main text and in the text written on diagram 40 also part of section 12. i will go through this in detail in the next few slides it is necessary to read appendix a of
01:33:05 it is necessary to read appendix a of approved document b to understand the fire definitions in table a6 of appendix a it explains the use
01:33:14 the use and definitions of non-combustible materials
01:33:18 materials in table a7 it explains the use and definitions of materials of limited combustibility class naught is defined separately in paragraph 13 of appendix a and class 1 is referred to
01:33:32 of appendix a and class 1 is referred to a paragraph 13 of appendix a also the fire propagation index i and the sub index
01:33:40 index little i1 as calculated in the part 6 test
01:33:44 test are referred to a paragraph 12 and paragraph 13 of appendix a only so knowledge of all these classes and indices is essential as well as
01:33:56 and indices is essential as well as knowledge of the non-combustible and limited combustibility definitions and i will now present each of these definitions in turn
01:34:12 non-combustible is defined in table a6 of approved document b there are two definitions for non-combustible provided as you can see highlighted on the screen
01:34:23 as you can see highlighted on the screen now
01:34:24 now each relies on either the national reaction to fire test data from part 11 r from part 4. these are the national class
01:34:33 class for non-combustible materials paragraph d
01:34:37 d the lower box marked here states that products classified as non-combustible under part four are non-combustible for the purposes of this guidance
01:34:49 the purposes of this guidance the other method referred to in table a6 is any material tested to bs-476 part 11 the method for assessing the heat emission from building materials
01:35:00 emission from building materials as shown in the upper blue box here
01:35:05 tom is holding up both samples again now as a reminder the part 11 test standard itself does
01:35:17 the part 11 test standard itself does not provide any limits on temperature rise or duration of flaming instead instead these are set out in appendix a only at point a as marked in the upper blue box
01:35:29 blue box there table a6 states that the material when tested to part 11 does not flame nor cause any rise in temperature on either the specimen or furnace thermocouple
01:35:41 thermocouple this is the national class for non-combustible also
01:35:48 the table on screen compares the two limits set for the national class non-combustible using table a6 of approved document 2013 so one can either do a part four test or
01:36:00 so one can either do a part four test or a part 11 tests all results must have been recorded as zero if one relies on part 11.
01:36:18 the second fire definition provided in approved document b is table ace is in table a7 use some definitions of materials of limited combustibility
01:36:29 combustibility this is a key definition regarding the products used on grenfell as the insulation material in the external wall should have been a material of limited combustibility
01:36:40 combustibility you can see in paragraph a that any material
01:36:44 material defined as non-combustible will also satisfy the national class for limited combustibility too the primary test that can be done to demonstrate limited combustibility
01:36:57 demonstrate limited combustibility using national test standards is part 11.
01:37:01 11. density limits are set as well as flame and temperature rise limits i have drawn out the text on the right hand side of the screen the column on the left hand side
01:37:13 the column on the left hand side provides references to specific sections of approved document b where limited combustibility is referenced with respect to the situations where such materials should be used
01:37:25 such materials should be used the references as shown in row eight of the table
01:37:29 the table apply only to insulation used as part of an external wall it is critical to understand the explicit explicit reference to insulation in the external wall made
01:37:42 to insulation in the external wall made in this table a7 the definition of a material of limited combustibility sets out not just temperature and
01:37:53 sets out not just temperature and flaming limits but also makes a distinction regarding the density of the insulation material
01:37:59 material if the material density is more than 300 kilograms per meters cubed the limit on specimen furnace temperature rises 20 degrees c with zero seconds of flaming to have
01:38:10 with zero seconds of flaming to have been observed in the part 11 test if the material is of density less than 300 kilograms per meters cubed the limits for observed flaming
01:38:21 the limits for observed flaming increased to a total of 10 seconds over the course of the whole test the limit on specimen furnace temperature rise is slightly higher at 25 degrees celsius with an additional limit set on specimen
01:38:33 with an additional limit set on specimen thermocouple temperature rise of 35 degrees c
01:38:38 degrees c the requirement for materials less than 300 kilograms per meters cubed density is therefore less onerous when relying on part 11 test it's worth noting that insulation
01:38:49 it's worth noting that insulation materials are often foam based and may well
01:38:52 well have a density less than 300 kilograms per meters cubed for example the density of phenolic foam and pir
01:38:59 and pir the insulation used on grenfell may have a density of around 35 kilograms per meter
01:39:10 cubed
01:39:14 however a material of limited combustibility is also referenced for another component of the external wall and this is a complex matter which i will try to explain carefully
01:39:27 will try to explain carefully in table a7 up at row six marked and blue here on the left there is a general row which states class not materials meeting the
01:39:38 class not materials meeting the provisions in appendix a paragraph 13a there at appendix a paragraph 13a it defines class naught as the highest
01:39:49 it defines class naught as the highest national
01:39:49 national product performance classification for lining materials this is achieved if a material or the surface of a composite product is one of two performances set the first
01:40:01 is one of two performances set the first being
01:40:01 being composed throughout of materials of limited combustibility therefore those materials must comply with the limit set in table a7 and this is done by means of the part 4
01:40:13 and this is done by means of the part 4 or part 11 test also again it is essential to be very aware
01:40:19 aware this is not part of the insulation row below
01:40:23 below highlighted in the orange box and i will come back to this matter again later
01:40:30 i want to now explain how approved document b refers to the classes 1 two three and four as calculated in the part seven surface spread of flame test
01:40:41 surface spread of flame test classes one to four are surface spread of flame classifications
01:40:48 and these are defined within part seven itself
01:40:52 itself it's not referred to again an approved document b
01:40:57 the horizonta the resulting class is simply a measure of how far along the specimen this flame spreads horizontally over two
01:41:04 over two time steps of the four classes class one is the highest and four is the lowest
01:41:11 lowest this means the flame travels the least horizontally along the surface when a material
01:41:16 material is a class 1 and it travels the furthest along the surface on a class 4 material the 1.5 minute measurement assesses the initial flaming
01:41:27 initial flaming so how quickly the material reacts immediately after it is exposed to high temperatures the final spread of flame shown on the screen also assesses how
01:41:38 shown on the screen also assesses how effectively the flame is sustained and can propagate along the surface the flame spread must be within both limits set for a class to achieve that class
01:41:52 i will now explain class naught
01:41:57 so class note has defined a paragraph 13 of appendix a it is stated as the highest national product performance classification for lining materials
01:42:08 lining materials and it is given two definitions as described in approved document b first as shown in the orange box a it is a product composed throughout of materials of limited combustibility as i
01:42:20 materials of limited combustibility as i explained earlier but there is a second definition relying both on the part six fire propagation index and part 7 the surface thread of flame test as shown in the blue box
01:42:33 test as shown in the blue box class 1 is obtained from part 7 and the fire propagation index and sub index is obtained from part 6. remember the calculations for the
01:42:44 remember the calculations for the indices in part six and how they are calculated from the gas temperatures measured in the chimney above the furnace as shown on the screen now
01:42:58 two temperature time curves are produced during the test the upper dark blue line on screen now is an example of the temperature measurement for a combustible specimen the lower light blue line on
01:43:10 specimen the lower light blue line on screen now is an example of the temperature measurement for the known non-combustible specimen tested as a benchmark in part 6.
01:43:21 from the graph of temperature versus time three distinct time periods are then considered from 0.5 to 3 minutes where the difference in temperature is calculated at 0.5 minute intervals
01:43:34 calculated at 0.5 minute intervals from 4 minutes to 10 minutes where the difference in temperature is calculated at one minute intervals and from 12 minutes to 20 minutes where the difference in temperature is
01:43:46 the difference in temperature is calculated at two minute intervals these values are then used in the formulae shown on the screen now to obtain s1 s2 and s3
01:43:57 the calculated s1 s2 and s3 values are then averaged to obtain little i1 2 and 3 where i is then the sum of these sub indices
01:44:08 indices please now look again at the definition of class naught on the screen martin yellow
01:44:13 yellow there it states for class naught the fire propagation index must be not more than 12
01:44:19 than 12 and sub index little i1 must be not more than
01:44:23 than 6 and so the test results from part 6 on a material or composite product must fall within these limits
01:44:34 fall within these limits additionally the class value of one must be achieved when the same product is tested to part seven
01:44:42 seven class one means the flame must not spread more than 165 millimeters from the heated end after 1.5 minutes into the test but in class 1 it must not also exceed
01:44:55 but in class 1 it must not also exceed this limit for the entire duration of the test for up to 10 minutes and i have shown you where class one is located most closely to the radiant panel shown on the screen
01:45:06 to the radiant panel shown on the screen now
01:45:12 because the fact that two test result types
01:45:15 types form the definition of class naught as so regularly ignored with the surface spread of flame test mostly only referred to when discussing class naught i think it's important i repeat this point again
01:45:28 it's important i repeat this point again that the class not material must be tested to achieve class 1 and test it again to determine its fire propagation index and fall under the limit set in
01:45:40 index and fall under the limit set in approved document b crucially regarding the external war wall at grenfell tower class note is also referred to within
01:45:52 class note is also referred to within diagram 40 which presents the provisions for external surfaces are walls taking grenfell tower as the building example
01:46:02 example the external surface classification was class not for the building because it had a dimension over 18 meters
01:46:10 meters and it was 1 000 millimeters more from the relevant boundary to adjacent buildings
01:46:16 buildings and this applied to the part of the building over 18 meters see the dark gray shading on the right hand side highlighted in yellow this meant the composite product used
01:46:28 this meant the composite product used for the external surface needed to have been tested to part seven the surface spread of flame and to achieve class one in that test and
01:46:37 and test it to part six and achieve a fire propagation index i not more than 12 and sub index little i1 not more than 6 exactly as set out on the right hand
01:46:49 exactly as set out on the right hand side of diagram 40 marked in the upper blue box some important points i suggest to the inquiry panel to note i have shown so far today that both part
01:47:01 i have shown so far today that both part 6 and part 7 tests can incorporate a composite specimen i have shown both tests do not directly heat the cut edge of the specimen
01:47:12 heat the cut edge of the specimen i've also shown that the scope of part 6 states
01:47:16 states it is for internal walls and ceilings the scope of part 7 states it is for walls
01:47:23 walls and ceilings and that it measures horizontal flame spread and i have shown class naught is referred to as the highest national product performance classification
01:47:35 performance classification for lining materials but i have also shown
01:47:38 shown it clearly referenced from this diagram 40
01:47:42 40 far external surfaces or walls for the purpose of exactly as written in the guidance this is in order to reduce the surface's susceptibility to ignition
01:47:53 susceptibility to ignition from an external source and to reduce the danger from fire spread up the external face of the building
01:48:06 some final points about class naught due to its significance to the work of this inquiry
01:48:12 inquiry so i now want to set out how long class naught
01:48:15 naught and the two tests upon which it relies part six and part seven have been referred to as the fire safety performance class for external walls in england and wales
01:48:29 the first national building regulations in england were the building regulations 1965.
01:48:35 1965. prior to this individual local authorities set their own performance requirements through local bylaws
01:48:42 bylaws london retained their own bylaws until 1985.
01:48:46 1985. in 1965 the external wall construction was not to include any combustible material except specific internal linings or specific external cladding
01:48:58 cladding the clouding is explained later on in regulation e7 at part 3b shown on screen now it required cladding on any external
01:49:09 it required cladding on any external wall
01:49:09 wall more than three feet from the boundary in a building greater than 50 feet in height
01:49:14 height to have a surface complying with the requirements for class naught class naught at that time was defined by prescribed construction typologies and with the only test referenced the
01:49:25 and with the only test referenced the surface spread of flame test as existed in 1953
01:49:32 the table on screen now shows the changes
01:49:35 changes in external wall requirements as defined in the national building regulations and then subsequently in approved document b through time in the following sides
01:49:47 through time in the following sides i have provided all of the supporting fire performance requirements and national definitions from 1965 up to the night of the fire i will not go through each one in detail
01:50:00 i will not go through each one in detail but instead i will point out some significant changes and that font is martin blue this is 1965 as i have just summarized
01:50:14 this is 1965 as i have just summarized in 1972 the external clouding above 15 meters was still required to achieve class naught however the definition was changed this year
01:50:24 year to refer to the newly introduced part 6 test
01:50:30 in 1976 external clouding above 15 meters was still required to achieve class naught however the definition of class note was changed again this year
01:50:41 changed again this year to refer to both part six and part seven tests
01:50:47 in 1985 the fire performance for the extraordin external war performance was dropped down from non-combustible to constructed of materials of limited combustibility
01:50:58 combustibility and the part 11 test standard was introduced there were some changes too to class naught and i will explain these later in 1992 for the first time a separate
01:51:10 in 1992 for the first time a separate journal was surfaced the insulation performance standard was a material of limited combustibility the definition of high rise increased from 15 to 20 meters
01:51:23 from 15 to 20 meters in 2000 an alternative for the external surface only was introduced by means of a bre fire note
01:51:31 note number nine with the insulation performance limits now set only for a ventilated cavity
01:51:39 cavity the definition of high rise was also lowered to 18 meters
01:51:45 in 2002 the european classification system was introduced as an alternative to the national classes in 2006 an alternative approach for the
01:51:57 in 2006 an alternative approach for the whole performance of the external wall was introduced by means of br 135 and the insulation definition changed again
01:52:06 again as shown on the slide
01:52:10 this has remained the case until 2013.
01:52:22 i have shown how class naught has been referred to in the building regulations and then the statute design guidance for that time period it's important for the panel to understand the primary changes to the
01:52:33 understand the primary changes to the definition of class naught in that time period
01:52:36 period also class naught was originally based on a surface spread of flame test only in 19 from the 1953's test standard but it was also defined in three
01:52:48 but it was also defined in three different ways either non-combustible throughout or a material with a non-combustible background and a specific tested fire performance of the surface
01:53:00 of the surface or a material with a combustible background but with a non-combustible face
01:53:05 face note the careful distinction between substrate
01:53:08 substrate and surface there were a few changes in the 1972 building regulations part six the fire propagation test had
01:53:19 part six the fire propagation test had been created by the bre in 1968 after they had identified that the highest classification class 1 from the surface spread of flame test
01:53:30 from the surface spread of flame test could not differentiate between different combustible linings the definition of class naught reference was therefore changed to refer to part 6 only
01:53:41 only the combustible substrate with the non-combustible surface definition was dropped
01:53:46 dropped leaving two options for the definition of class naught instead of three again constructed as throughout was retained
01:53:55 retained and the second option are shown on the screen now relying on the part six test
01:54:04 this changed again in 1976 when the definition of class naught became defined based on both part six and part seven
01:54:11 seven and this combination of tests has been relied on ever since the two distinct definitions for class naught remained either constructed throughout with non-combustible materials
01:54:23 non-combustible materials or a surface tested with the substrate as shown
01:54:26 as shown on the slide
01:54:30 however in 1985 the definition of class north was significantly changed first the definition stopped relying on non-combustible materials and instead a class not material or
01:54:42 and instead a class not material or surface of a composite product could be composed throughout of materials of limited combustibility a lower standard secondly the requirement to consider the substrate
01:54:53 requirement to consider the substrate with the surface was removed from the text in the statutory guidance document this remained the definition to the time of the grantful fire
01:55:09 during the primary refurbishment works the national class standards were relevant
01:55:14 relevant these were first referring to section 12 of proof document b in accordance with external surfaces at section 12.6 the external surfaces of
01:55:25 at section 12.6 the external surfaces of walls should meet the provisions in diagram 40 and there the national class naught is cited as i have explained and for insulation materials and products at section 12.7
01:55:37 products at section 12.7 in a building with the story 18 meters or more above ground level any insulation product filler material not
01:55:44 not including gasket sealants and similar etc
01:55:48 etc used in the external wall construction should be of limited combustibility
01:55:54 the cellatex fr 5000 rs 5000 and the kingspan k15 insulation were presented as achieving national class naught
01:56:04 naught they were not presented as the required material of limited combustibility
01:56:11 adb and table a7 for materials of limited combustion materials of limited combustibility at row eight fire insulation makes no reference to class naught the
01:56:28 makes no reference to class naught the archonic renault bond panels were also presented as achieving a national class on their bba agreement certificate which stated behavior in relation to fire
01:56:40 stated behavior in relation to fire in relation to the building regulations for reaction to fire the panels may be regarded as having a class not
01:56:47 class not surface
01:56:50 this certificate then goes on to state at 6.2 if you look at that on the screen a fire retardant sample of the product with the metallic gray
01:57:01 with the metallic gray pvdf finish when tested in accordance with part
01:57:04 with part 6 achieved a fire propagation index i of 0 and when tested in accordance with part 7
01:57:12 part 7 achieved a class 1 surface spread of flame
01:57:15 flame it goes on to state at 6.3 as a consequence of section 6.1 which i will explain later and section 6.2 as shown on the screen
01:57:26 and section 6.2 as shown on the screen now
01:57:27 now the products may be regarded as having a class not surface in relation to the approved document b of the building regulations 2000.
01:57:41 i wanted to show you the test results from the test report upon which the bba relied there you can see the fire propagation index is recorded as one
01:57:54 index is recorded as one and the sub index little i1 as zero
01:58:02 and that concludes my section of the presentation on the national classes and classifications thank you just going to do a short pause
01:58:46 hmm okay i will now explain the european reaction to fire tests
01:58:56 it is useful to note that some of the test methods are similar to those relied upon
01:59:01 upon in the national class system and others are very different also there's a dedicated classification process
01:59:09 process presented in a bespoke classification standard
01:59:13 standard therefore the european system does not rely on definitions within the statutory guidance document as occurs for the national classes i'm going to explain four european test
01:59:25 i'm going to explain four european test standards
01:59:26 standards unlike the british tests which all sit within the 476 series of tests the european reaction to fire tests each have their own unique numbering as does the associated classification
01:59:39 as does the associated classification standard
01:59:39 standard which is called bsen 13501 part one first i will explain each of the four tests and then i will explain the classification standard
01:59:53 the european reaction to fire standards are issued by cen this is the european committee for standardization it is an association that brings together the national standardization
02:00:05 together the national standardization bodies of 34 european countries cen is made up of a series of committees and subcommittees that issue standards the overarching
02:00:16 issue standards the overarching technical committee for fire safety is cen tc127 fire safety and buildings the subcommittee that is responsible for reaction to fire is
02:00:28 is responsible for reaction to fire is called working group four and i have provided the references on the slide for the record unlike the british standards the industry government bodies that draft
02:00:39 industry government bodies that draft the european standards are not listed within it based on information available on the cen website the chairperson of the overarching technical committee for fire safety and
02:00:51 technical committee for fire safety and buildings is listed as dr debbie smith a director of bre and the convener of work in group four is a mr
02:01:00 is a mr roy veghurst head of regulatory affairs at kingspan
02:01:07 before i introduce the european reaction to fire test standards i want to highlight this quote from berget messerschmitt an employee of rockwell international in denmark
02:01:18 denmark at the time she gave a presentation at the fire seat conference at edinburgh university in 2008. she raised the issue of a new reference standard for externally applied
02:01:30 standard for externally applied products and stated the work to define a new
02:01:33 new test method for facades have been transferred to eota again i've provided the references on the slides eota is the european organization for
02:01:45 eota is the european organization for technical assessment in the area of construction products and it is based in brussels there are eight companies listed
02:01:54 listed in the uk membership area including the bre
02:01:58 bre the bba and exovo warrington fire there are four european reaction to fire tests referenced by the classification standard for
02:02:11 by the classification standard for construction products each part addresses a different element of contribution in a fire bsen iso 1182
02:02:22 bsen iso 1182 is a test of non-combustibility for materials
02:02:25 materials bsen iso 1716 is a test to determine the growth heat of combustion in a bomb calorimeter bsen
02:02:37 in a bomb calorimeter bsen 13823 tests how a specimen reacts when exposed to thermal attack by a single burning item in the corner of a room and finally bsen
02:02:49 in the corner of a room and finally bsen iso 11925-2 measures the extent of vertical fire spread and production of flaming droplets and particles when a specimen is exposed to a single flame
02:03:02 specimen is exposed to a single flame source
02:03:02 source for a defined period of time only
02:03:08 the first european reactant fire test i will describe is the non-combustibility test the 2010 version was relevant during the grenfell tower refurbishment it is cited as the fifth edition of
02:03:21 it is cited as the fifth edition of fifth edition of the standard cancelling and replacing the fourth edition before it this test is used for determining the non-combustibility performance
02:03:33 non-combustibility performance under specified conditions of homogeneous products and substantial components of non-homogeneous products the test apparatus is very similar to that used in bs 476 part 11
02:03:46 that used in bs 476 part 11 as it comprises an electric furnace capable of maintaining a steady temperature of 750 degrees c in the european test the thermocouples
02:03:57 in the european test the thermocouples are used to measure the temperature within the furnace a specimen thermocouple can be added optionally and it is not subsequently used in the classification
02:04:09 five cylindrical specimens are prepared each with a diameter of 45 millimeters and a height of 50 millimeters they are tested individually but data is required from all five
02:04:21 but data is required from all five specimens to determine the final test result if the thickness of the material is different to 50 mil specimens may be layered and then secured with steel wires or the
02:04:33 then secured with steel wires or the material thickness may be adjusted tom is now holding up examples of these specimens for the european test
02:04:52 specimens for the european test to the test specimens are conditioned and each specimen is weighed and its mass recorded
02:05:05 i'm showing a video of this test now
02:06:03 [Music]
02:06:42 as you can see very detailed requirements are set out for the temperature measurements in this test
02:06:50 test the initial temperature the maximum temperature and the final temperature um as well as the specimen center thermocouple and the final specimen center thermocouple
02:07:02 specimen center thermocouple so a lot of data is produced in this test
02:07:07 the test report has to include a general description of the product tested including the density mass per unit area and
02:07:14 and thickness together with the form of construction of the test specimen and the statement that the test results relate to the behavior of the test specimens of a product under the particular conditions of the
02:07:26 under the particular conditions of the test they are not intended to be the sole criterion for assessing the potential fire hazard of the product and use so the same statement again
02:07:41 so the same statement again the second european reaction to fire test i will describe is bsen iso 716 1716 determination of the growth heat of combustion
02:07:52 combustion heat of combustion is defined as the thermal energy produced by combustion of a unit mass of a given substance gross heat of combustion is the heat of combustion of a substance when the
02:08:04 combustion of a substance when the combustion is complete complete and any produced water is entirely condensed
02:08:09 condensed under specified conditions this test specifies a method for determining the growth heat of combustion in a rig called bomb calorimeter
02:08:21 in a rig called bomb calorimeter the version dated 2010 was the version relevant during the refurbishment and it is cited as the fourth edition of this test standard the image on screen now shows the bomb
02:08:33 the image on screen now shows the bomb calorimeter apparatus there are two main components the bomb and the calorimeter
02:08:42 the bomb is a water type vessel and contains pure oxygen the bomb is contained within a larger enclosure which is filled with water when the specimen is burnt
02:08:53 with water when the specimen is burnt in the inner water type vessel it releases heat which is transferred through the walls of the vessel into the water surrounding it and in doing so heats up the water
02:09:04 doing so heats up the water the increase in water temperature is measured using a thermometer and a stirrer driven by a constant speed motor
02:09:11 motor is placed in the calorimeter 50 grams of the specimen is taken and ground into a fine powder
02:09:23 ground into a fine powder tom is now holding up a small bag of 50 grams of ground polyethylene
02:09:42 0.5 grams of the specimen is placed in a crucible
02:09:46 crucible along with 0.5 grams of benzoic acid this is to assist the sample to combust this crucible is just a non-combustible holder that is used to store the material within the bomb
02:09:59 material within the bomb the specimen is not directly exposed to flame but a firing wire is inserted into the crucible holder when an electrical current is passed through this wire the material is ignited and the
02:10:10 the material is ignited and the temperatures begin to rise it's important to note that metal powders are not suitable for use in the bomb calorimeter as they represent an explosion hazard due to over
02:10:22 an explosion hazard due to over pressures
02:10:22 pressures created within the test vessel therefore if our metallic components are present within a composite material their gross heat or combustion is deemed to be zero
02:10:33 to be zero and no test is required i will show you a video of this test now
02:11:22 um
02:12:33 so again very detailed activities are required
02:12:37 required in but as defined in the test standard 3.5 gram specimens are tested and the gross heat of combustion for each is then calculated based on
02:12:49 each is then calculated based on the increase in temperature of the water this can be done as it is a scientific constant that it takes 4184 joules of heat energy to heat one kilogram of water by one
02:13:02 to heat one kilogram of water by one degree
02:13:03 degree as the quantity of water in the calorimeter is a known value the amount of energy it took to heat up can be back calculated the average of the three specimen results is taken and the final result is
02:13:15 results is taken and the final result is given in units of joules or megajoules to be a valid test the results must comply
02:13:22 comply with the criteria shown in table 1 on the slide
02:13:29 the test report has to include the information as i have shown on the screen
02:13:34 screen including the similar statement i've referred to a few times this morning third european reaction to fire test i
02:13:46 third european reaction to fire test i will now describe is known as the single burning item test this british standard is the uk implementation of a european norm and the 2014
02:13:58 of a european norm and the 2014 version was relevant to the grenfell tower refurbishment it superseded a 2010 version which was
02:14:10 withdrawn
02:14:14 in the single burning item test a specimen forming a corner is tested tom is now standing to an exact two-scale replica of the bsen 13823
02:14:27 of the bsen 13823 single burning item test specimen
02:14:32 [Music]
02:14:38 the specimen holder is a metal frame with the calcium silicate board facing called the backing board the specimen to be tested is then fixed onto the backing board
02:14:49 the backing board according to the fixing conditions in the end use application required the specimen holder comprises two wings designated a short and a long wing it is the largest
02:15:01 and a long wing it is the largest specimen
02:15:02 specimen used in any of the reaction to fire tests in either europe or nationally the long wing has a length of one meter and a height of 1.5 meters
02:15:13 and a height of 1.5 meters the short wing has a height of 1.5 meters but a shorter length of 495 millimeters the maximum depth or thickness of the
02:15:24 the maximum depth or thickness of the total specimen tested in the single burning item test is 200 millimeters
02:15:32 specimens with a normal thickness greater than 200 millimeters are again cut away from the unexposed side so they fit into the tess rig materials with the thickness less than
02:15:43 materials with the thickness less than 200 millimeters are tested at their normal thickness with no requirement for scaling up a total of three specimens are tested and both long and short wings must be
02:15:54 and both long and short wings must be replaced after each test run
02:16:00 the single burning item test also refers to further information about how the specimen is mounted in its end-use application including the presence of substrates
02:16:12 including the presence of substrates these are products used immediately beneath beneath the product about which information is required
02:16:20 required the single burning item test standard sets out clear guidance regarding the issue of mounting and substrates this is the test upon which arconic relied
02:16:30 relied regarding renault bond products
02:16:35 when products are tested and mounted as in their end-use applications the test results are then valid
02:16:43 valid only for that application when products are tested using a standard mounting additional guidance is provided for example boards in the end-use application of a ventilated cavity
02:16:55 application of a ventilated cavity behind
02:16:56 behind it shall be tested with the cavity of at least 40 millimeters boards to be mechanically fixed to a substrate and their end use should be test fixed to a substrate
02:17:08 should be test fixed to a substrate using appropriate fixings and products that in their end use application are glued to a substrate shall be tested glued to a substrate
02:17:21 the test rig contains two burners a primary burner as shown in the diagram and an auxiliary burner and i will explain that next this primary burner is located at the
02:17:34 this primary burner is located at the corner of the two wings offset from the front face by 40 millimeters it is a triangular tray filled with sand with two equal sides of 250 millimeters
02:17:45 with two equal sides of 250 millimeters and a height of 80 millimeters a gas pipe is attached to the tray so the gas flows through the sand diffusing it the burner is calibrated to give a heat
02:17:57 the burner is calibrated to give a heat output of 30.7 kilowatts which is intended to represent a waste paper bin on fire in the corner of the room although the burner is offset from the front face
02:18:09 burner is offset from the front face flames given off by the burner can make direct contact with the outside face of the test material the auxiliary burner is located remote
02:18:20 the auxiliary burner is located remote from the test apparatus on a post opposite to the specimen corner
02:18:25 corner and at a height of 1.45 metres from the floor
02:18:29 floor the auxiliary burner is ignited with the same propane gas supply as the primary burner
02:18:35 burner but simply to provide a baseline average burner
02:18:39 burner heat and smoke output at the start of the test
02:18:43 the test in order to subtract the contribution of the primary burner from the measured results at the end of the test
02:18:50 the test and to carry out calculations with the results and attribute them only to the specimen
02:18:56 specimen the only purpose of the auxiliary burner is to run it for a period of 180 seconds before the primary burner is ignited and then subtract those values from the total heat and
02:19:08 those values from the total heat and smoke output of the burner and specimen at the end of the main test
02:19:20 at the end of the main test an exhaust system is located above the test apparatus in addition to the practical purpose of extracting smoke from a burning specimen several measurements are taken in the
02:19:31 several measurements are taken in the duct exhausting the smoke these are thermocouples to measure the temperature of the smoke a pressure pressure sensing probe to measure the flow-induced
02:19:42 measure the flow-induced pressure difference in the duct a gas sensor that measures the oxygen and carbon dioxide content of the air being extracted
02:19:51 extracted and a light source and light sensor that shines through the smoke to measure how much light is being blocked hence how dense the smoke is
02:20:02 smoke is the video on screen now shows the test procedure
02:20:05 procedure for the single burning item tests
02:21:43 so again there are very detailed sets of requirements for the data to be produced for the data to be measured in this test the horizontal flame spread is recorded
02:21:54 the horizontal flame spread is recorded as the occurrence of sustained flames reaching the far edge of the long-winged specimen
02:22:00 specimen the fall of flaming droplets or particles shall be recorded only within the first 600 seconds of the exposure
02:22:08 exposure period and only when the droplets or particles
02:22:11 particles reach the floor level of the trolley outside the burner zone after 26 minutes the gas supply is terminated and the automatic recording is also stopped
02:22:22 stopped and i've explained all the sensors in the exhaust duct these quantities are recorded automatically and used to calculate the volume flow the heat release rate and the smoke
02:22:34 the heat release rate and the smoke production rate from the specimen during the test
02:22:41 section 9 of the standard sets out how the results of this test must be expressed
02:22:47 expressed there is a lot of data and analysis required
02:22:50 required and it is essential to read the bsen in full to understand this these are key to the european classes in short the burning behavior is
02:23:01 in short the burning behavior is represented by a series of graphs showing the average heat release rate the total heat release rate and the fire growth rate indices versus time
02:23:12 time the smoke production behavior is given as a further series of graphs of the average smoke production the total smoke production and the smoke growth rate index
02:23:24 and the smoke growth rate index later in the classification standard the designation little s will appear and it is calculated here the production of flaming droplets and particles must be confirmed as an
02:23:36 particles must be confirmed as an occurrence or not for the product later in the classification the designation little d will appear and it is calculated here
02:23:47 and it is calculated here on the slide now are the requirements to be included in the test report again a general description of the product tested including its density mass form of construction
02:23:58 construction description of the substrate and fixing to the substrate must be recorded and again that statement regarding the test results
02:24:12 annex a of this standard goes on to set out in detail the series of parameters that must be calculated to evaluate the performance of the product i've marked only some of them in
02:24:23 product i've marked only some of them in yellow here these include the total heat release rate noted as thr on the screen and the fire growth rate indices
02:24:33 indices noted as figure values on the screen but all of the calculations listed here must be carried out using the test data
02:24:46 the standard provides a detailed calculation method for thr 600 s which i have shown on the screen now i am not going to talk through these equations today
02:24:58 equations today but instead it's to note that thr 600 s is defined as the total heat release rate of the specimen in the first 600 seconds of the exposure
02:25:09 in the first 600 seconds of the exposure period
02:25:13 the standard provides a calculation method for figra which i have shown on screen now and again i'm not going to talk through these equations today
02:25:23 figra has also has a very complex definition which i've presented on the screen
02:25:29 screen here and i will come back to that again later
02:25:37 it is a little easier to understand the data analysis by observing here how the results are then presented in a test report on screen now are the heat release rate versus time
02:25:49 are the heat release rate versus time thr
02:25:50 thr and figara graphs for the arconic renault bond 55 pe riveted panel
02:25:59 ultimately as i've presented already section 9 of the test standard sets out exactly how the results of the test must be expressed and all the calculations i have shown
02:26:11 and all the calculations i have shown result in this required expression as shown again on the screen here these results are referred to for nearly every european class so despite their complexity an awareness
02:26:23 so despite their complexity an awareness of them
02:26:24 of them helps in understanding the european classifications later in my presentation finally the fourth european reaction to
02:26:37 finally the fourth european reaction to fire test
02:26:38 fire test is bsen iso 11925 part 2. the ignitability of building product
02:26:45 product products subjected to direct impingement of flame
02:26:50 of flame this is referred to as the european single flame source test it is designed to simulate a small flame
02:26:58 flame being directly applied to the surface or to the edge of a material the standard is dated 2010 as the version relevant to the grenfell tower refurbishment
02:27:09 refurbishment it superseded a version dated 2002 which was withdrawn
02:27:18 on screen now is the apparatus for the single flame source test the apparatus comprises of a bunsen burner
02:27:27 burner housed within an outer housing called the combustion chamber
02:27:33 the image on screen now shows a cross section through the combustion chamber looking side on the sample is suspended from the back wall of the outer housing and the bunsen burner is mounted onto a
02:27:45 and the bunsen burner is mounted onto a horizontal plate so that it moves smoothly forwards and backwards
02:27:51 backwards in a horizontal plane along the center line of the combustion chamber an aluminium tray containing sheets of paper is
02:28:00 paper is placed below the sample so that any flaming droplets will land on the paper and potentially ignite the paper
02:28:10 a test specimen 250 millimeters long by 90 millimeters wide is prepared the maximum permitted thickness of the specimen is 60 millimeters
02:28:21 specimen is 60 millimeters a material that is normally less than 60 millimeters can therefore be tested to its full thickness and a material that is greater than 60 millimeters should be cut down from the unexposed side to fit into the
02:28:34 from the unexposed side to fit into the test rig
02:28:36 test rig tom is now holding up a two scale replica
02:28:39 replica of the test specimen
02:28:48 as stated on the screen a total of six representative specimens are required in one test
02:28:55 one test another key point is if a product is installed
02:28:59 installed with covered edges but can also be used with
02:29:02 with unprotected edges tests shall be performed
02:29:06 performed on both covered and uncovered specimens this is different to part 6 and part 7 discussed earlier where the tests are designed to prevent edge exposure
02:29:18 edge exposure again the issue of incorporating the influence of the substrate on the specimen behavior is addressed clearly in the standard
02:29:28 the specimen is vertically mounted into the test frame a burner is fitted on a track and applies a flame directly to the surface of the material this burner uses a propane gas fuel
02:29:40 this burner uses a propane gas fuel and the flame length must be calibrated to be no longer than 20 millimeters you can see in the diagram on the left that the flame is angled at 45 degrees two different exposures are used
02:29:53 degrees two different exposures are used surface exposure and edge exposure a surface exposure test must always be undertaken edge exposure tests are only undertaken
02:30:04 edge exposure tests are only undertaken if the edges can be exposed under end conditions therefore if in the envisaged end-use application direct flame attack on the edge cannot occur
02:30:14 occur the product does not need to be tested when a surface exposure is used the flame is applied 40 millimeters up from the bottom of the specimen on its front face
02:30:25 its front face a reference line is marked on the sample and i will show you this on the next slide
02:30:30 slide when an edge exposure is used the flame is applied on the bottom edge of the specimen
02:30:40 the flame is then applied to the material for either 15 or 30 seconds depending on the classification the sponsor wishes to obtain the higher european class b down to the
02:30:52 the higher european class b down to the european class d are based on a 30 second exposure once the flame is applied the extent of vertical flame spread is observed and recorded
02:31:04 recorded the image here is from a test video that we'll watch in a few moments the bottom blue line is the 40 millimeter line where the flame is applied for a surface exposure test and the second line marks 150
02:31:17 test and the second line marks 150 millimeters above the flame application point
02:31:22 point if the flame application time is 15 seconds
02:31:25 seconds then the end of test is 20 seconds to allow five seconds of observation time if the flame application time is 30 seconds then the end of test is at 60
02:31:37 30 seconds then the end of test is at 60 seconds
02:31:38 seconds allowing a further 30 seconds observation time
02:31:44 for the edge exposure version of the test the burner has specific required locations set out in the test standard
02:31:52 standard for a material greater than three millimeters thick but less than 10 millimeters the flame is applied to the underside using the 45 degree angled burner 1.5 millimeters behind the front phase
02:32:05 1.5 millimeters behind the front phase of the specimen this is whether it's a single layer as shown by the image on the left or multiple layers as shown in the figure on the right
02:32:17 where the material is less than three millimeters thick the flame is applied at the midpoint of the bottom edge as shown in this test standard
02:32:29 for all multi-layered products greater than 10 millimeters an additional set of tests shall be carried out with the specimen turned at 90
02:32:38 90 degrees around its vertical axis and the flame impinging at the bottom edge of the center line of each different layer a test is done for each of the layers that make up
02:32:50 for each of the layers that make up the sample
02:32:54 i'm now showing you a video of this test
02:33:04 procedure
02:34:09 regarding the results first it is noted whether the flame extent reaches the 150 millimeter line marked on the screen also the presence of any flaming on the specimen once the pilot flame is removed
02:34:22 specimen once the pilot flame is removed as recorded the test report must identify whether any flaming debris falling from the specimen ignites the filter paper on the slide now are the requirements
02:34:34 on the slide now are the requirements for the test report the results of the test shall be expressed by a record of the following the position of flame application whether ignition occurs whether that
02:34:45 whether ignition occurs whether that flame tip reaches 150 millimeters above the flame application point and the time of which this occurs presence of flaming droplets or particles which cause ignition of the
02:34:56 particles which cause ignition of the filter paper and observations of physical behavior of the test specimen again the test report has to include a general description of product tested the form of construction
02:35:08 product tested the form of construction of the specimen including the description of substrate used and methods of fixing this test also requires information on the intended application of the product
02:35:20 the intended application of the product if known and it contains the same statement again
02:35:28 to finish this session finally when i was explaining the single burning item test
02:35:34 test earlier the large-scale specimen heated in the corner i mentioned that smoke production and flaming troplets were recorded in that test i have also explained that flaming droplets are
02:35:46 explained that flaming droplets are recorded in this last test the single flame source test in the classification standard which i'm about to explain it sets limits for little s and little d
02:35:58 it sets limits for little s and little d as shown on the screen it is useful to understand the smoke production is obtained
02:36:03 obtained from the single burning corner test only whereas the flaming sorry excuse me whereas the flaming droplet performance is obtained from both the single burning item
02:36:14 both the single burning item and single flame source test this ends my description of the detailed test procedures presented in the four european reaction to fire test standards
02:36:26 european reaction to fire test standards good thank you very much indeed mr timmy i think that's the moment that we were going to take lunch yes um so where in your hands we could we could either take around an hour
02:36:37 hour and begin again at quarter to two or just to be aware i think there's around an hour's worth of presentation probably just under an hour just under an hour left so equally we could break now and start again at two well
02:36:49 break now and start again at two well i'm going to ask dr elaine what she'd prefer to do i i think that i've i'm communicating an extensive quantity of information so maybe we should wait till too i'm very happy yeah if you're happy to do that yeah this
02:37:01 if you're happy to do that yeah this turn is yeah yeah right well we'll stop at that point and then resume it two o'clock okay thank you thank you very much
02:37:22 yes thank you very much
02:38:05 you